The present invention relates to measuring electromagnetic emission from component or circuit boards mounted in racks, i.e. in the usual way in parallel to each other with a common connection plane, on one side of which the connections to the boards are located. The invention also relates to measuring interference sensitivity to electromagnetic radiation coming from the outside in such an individual component or circuit board, i.e. the influence of the radiation on the signal transmission between the electronic circuits on the board and therefrom to the connections of the board in the connection plane.
Authorities in different countries make ever harder demands on the amount of electromagnetic radiation which is allowed to be emitted by electronic equipment. Emission of electromagnetic radiation thus must be restricted as much as possible. For electronic equipment, in which several component or circuit boards are mounted in parallel in a common connection plane, there is for natural reasons particular difficulties in measuring the emitted radiation from each individual board.
From the document AT & T Technologies, Technical Digest No. 73, January 1984, "Circuit Pack Adaptor for High-Speed Circuit Packs", it is, in the testing of electronic equipment previously known to mount an individual circuit board on the rear side of the backplane or connection plane conventionally used in a computer. This mounting of the individual board makes the conductors on the board accessible for connection to electric testing equipment. The device mentioned in this document can however not be used for the measurement of the electromagnetic radiation which is emitted from the circuit board connected at the rear side, since radiation emitted from this card is mixed with the radiation emitted from the other boards. Nor is this device suited to be used for testing the interference sensitivity of an individual board, since a possible fault appearing in the electronic device, as a whole, of which an individual board is a part, not securely can be traced to have appeared in this board.